Thailand's telecommunications regulator has approved in principle a plan to issue special SIM cards to foreign tourists so they can be tracked through their mobile phones.

Officials at the National Broadcasting and Telecommunications Commission said the plan would apply to tourists only, backtracking on an earlier announcement that it would cover all foreigners, including resident aliens on long-term visas, the Bangkok Post and other media reported Wednesday.

The commission said the plan would be studied further after its endorsement Tuesday. Foreign and Thai users are already required to register when purchasing SIM cards.

State surveillance of online activity is high under the military government installed after a 2014 coup, and there have been dozens of arrests of people for political material posted on Facebook and other sites.

NBTC Secretary-General Thakorn Tanthasit suggested that the plan would not only help catch terrorists and criminals, but also help find travelers who have gotten in trouble or gone missing.

"We are not limiting any rights. The National Broadcasting and Telecommunications Commission has no authority to check on the location of users," he was quoted as saying by the Bangkok Post. "But if tourists commit wrong, or there is a court warrant, we will then forward the warrant to a mobile phone operator and seek cooperation."

His failure to explain details of the plan has caused skepticism, since it is unclear how the special cards would differ from normal SIM cards, which already can be used for tracking phones. He was not available to answer repeated calls to his office.

AIS, the country's leading cell phone service provider, said in a statement Wednesday to The Associated Press that it "would be happy to comply" with the plan if it helps ensure national stability. The statement noted the existing requirement for everyone, Thai and foreigner alike, to register when buying a SIM card.

Poomjit Sirawongprasert, president of Thai Hosting Service Providers Club and a strong advocate of free speech online, described the plan as useless, especially if is meant to capture criminals or terrorists. The use of roaming SIMs from other countries, or having a Thai citizen purchase a card for a foreigner, could evade monitoring, she said.